A railway includes two types of routes: a route provided with a facility that supplies power to a train from the ground through a trolley wire or a third rail (hereinafter, called “electrified route”); and a route without a power supply facility from the ground, in which power generation means included in the train obtains power (or motive power is obtained from a motive power source) (hereinafter, called “non-electrified route”). In the electrified route, regenerative electric power generated during braking of the train can be consumed by another train. Therefore, the energy efficiency is generally higher in the electrified system, and there is a tendency to preferentially electrify routes with a greater number of trains. Recently, a plan for electrifying non-electrified routes is developed on the background of the rise in the energy price.
Meanwhile, a train that can travel regardless of whether the route is electrified or non-electrified is desirable to efficiently operate the train. An example of widely used means for realizing such a train includes a system of pulling a train formation including vehicles without electric power sources/motive power sources by an electric locomotive in the electrified route and pulling the train formation by a diesel locomotive including an internal combustion engine as a motive power source in the non-electrified route.
Regardless of whether the locomotive is an electric locomotive or a diesel locomotive, a locomotive is provided with a large number of apparatuses, and the weight of the locomotive is usually several times higher than the weight of a passenger car constituting the train. For example, compared to a power-dispersed train, such as a Shinkansen train travelling in Japan, in which a driving device and other functions necessary for the train are dispersed, the locomotive has a problem that the track is significantly damaged by a heavy axle or has a problem that there is a limit to speeding up the train because a large-capacity brake device is necessary for a vehicle with concentrated weight.
On the other hand, a function-dispersed train needs to have the functions optimized for each of the electrified route and the non-electrified route, and there is a problem that the functions cannot be shared.
To solve the problems, Patent Literature 1 provides a railroad-vehicle driving device and means for realizing a railroad-vehicle using the railroad-vehicle driving device, the device including: power generation means based on an overhead contact line voltage or a diesel engine (and fuel cells/gas cells), that is, different power sources (FIGS. 1: 11, 12, 21, and 31 in Literature 1); and power converters that convert power obtained from the power sources to DC voltages to change the power to DC voltages (FIGS. 1: 13, 20, and 32 in Literature 1), wherein the problems can be solved by appropriately switching the power sources and the power converters according to the travelling route.